Transfusion triggers in critical care 13th CCSK annual meeting 2026
By Marcus D. Lance
Transfusion in the Intensive Care setting still occurs in 25 to 50% of all admitted patients. The indication for transfusions varies according to the level of urgency and reasons. In 80%, the main indication for RBC transfusion is a low hemoglobin level. In contrast, are active hemorrhage and hemodynamic instability only to a lesser degree (27%/23%) leading to transfusion 1. Interestingly, about 95% of the intensive care patients will be anemic on day 3 after admission regardless of transfusion.
Although blood and blood product transfusion may be live saving, there are disadvantages of all commonly used blood products (e.g. transfer of infections, TRALI, TACO, immunomodulation). In addition, blood and blood products are scarce resources 1 2.
Since the milestone study by Hérbert et al. in 1999, the restrictive transfusion strategy for critically ill patients with hemoglobin levels between 7-9 g/dl was introduced and found acceptance of current guidelines 2-5.
Although multiple studies supported the restrictive transfusion strategy in different settings, some recent investigations demonstrated potential beneficial effects of higher thresholds.
In 2015, de Almeida and co-workers showed in a cohort of critically ill patients after cancer surgery, that a liberal transfusion practice (trigger <9g/dl) might be associated with less major complications 6. However, in this population, blood transfusion is associated with return of metastasis and cancer 7.
While in cardiac surgery the strategy still advocates for restrictive approach, the MINT trial suggested patients with acute myocardial infarction may benefit of more liberal transfusion triggers 8 9.
Likewise, in patients with neurological injuries suffering of stroke, traumatic brain injury (TBI) or subarachnoidal hemorrhage there is controversy about which threshold should be kept 10. Recently, the liberal strategy was investigated in a cohort of TBI patients. Hence, there was no favorable outcome regarding neurological outcomes 11. In the same year, Taccone et al. published a study suggesting the threshold for transfusion of <9g/dl-called liberal- is resulting in less unfavorable neurological outcomes 12.
Although some of the contradictive results may be based on the different definitions of restrictive and liberal transfusion practice, a strict adherence to hemoglobin levels as trigger for blood transfusion might not be the best option. Therefore, some proposals apply physiological transfusion triggers which might be a more appropriate way to address the differences of disease state. For example, could the central venous oxygen saturation, the mixed venous oxygen saturation, oxygen extraction and lactate levels help to determine the need for blood transfusion 13.
Future research should focus on feasibility of physiological parameters to decide on blood transfusion. In addition, the combination of parameters with or without hemoglobin levels could be integrated even with support of AI tools to establish more accurate triggers for blood transfusion.
References:
1. Yadav SK, Hussein G, Liu B, et al. A Contemporary Review of Blood Transfusion in Critically Ill Patients. Medicina (Kaunas) 2024;60(8) doi: 10.3390/medicina60081247 [published Online First: 2024/08/31]
2. Vlaar AP, Oczkowski S, de Bruin S, et al. Transfusion strategies in non-bleeding critically ill adults: a clinical practice guideline from the European Society of Intensive Care Medicine. Intensive Care Med 2020;46(4):673-96. doi: 10.1007/s00134-019-05884-8 [published Online First: 2020/01/09]
3. Hébert PC, Wells G, Blajchman MA, et al. A multicenter, randomized, controlled clinical trial of transfusion requirements in critical care. Transfusion Requirements in Critical Care Investigators, Canadian Critical Care Trials Group. N Engl J Med 1999;340(6):409-17. doi: 10.1056/nejm199902113400601 [published Online First: 1999/02/11]
4. Coz Yataco AO, Soghier I, Hébert PC, et al. Red Blood Cell Transfusion in Critically Ill Adults: An American College of Chest Physicians Clinical Practice Guideline. Chest 2025;167(2):477-89. doi: 10.1016/j.chest.2024.09.016 [published Online First: 2024/09/29]
5. Carson JL, Stanworth SJ, Guyatt G, et al. Red Blood Cell Transfusion: 2023 AABB International Guidelines. Jama 2023;330(19):1892-902. doi: 10.1001/jama.2023.12914 [published Online First: 2023/10/12]
6. de Almeida JP, Vincent JL, Galas FR, et al. Transfusion requirements in surgical oncology patients: a prospective, randomized controlled trial. Anesthesiology 2015;122(1):29-38. doi: 10.1097/aln.0000000000000511 [published Online First: 2014/11/18]
7. Etheridge J, Shah P, Stanworth SJ, et al. Association between peri-operative red blood cell transfusion and cancer recurrence in patients undergoing major cancer surgery: an umbrella review. Anaesthesia 2025;80 Suppl 2(Suppl 2):65-74. doi: 10.1111/anae.16501 [published Online First: 2025/01/08]
8. Casselman FPA, Lance MD, Ahmed A, et al. 2024 EACTS/EACTAIC Guidelines on Patient Blood Management in Adult Cardiac Surgery in Collaboration With EBCP. J Cardiothorac Vasc Anesth 2025;39(8):1964-2018. doi: 10.1053/j.jvca.2024.10.006 [published Online First: 2025/05/24]
9. Carson JL, Brooks MM, Hébert PC, et al. Restrictive or Liberal Transfusion Strategy in Myocardial Infarction and Anemia. N Engl J Med 2023;389(26):2446-56. doi: 10.1056/NEJMoa2307983 [published Online First: 2023/11/12]
10. Shaukat A, Zahoor MA, Khan K, et al. Liberal Versus Restrictive Blood Transfusion Strategies in Neurocritical Care: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Crit Care Res Pract 2026;2026:6179847. doi: 10.1155/ccrp/6179847 [published Online First: 2026/01/14]
11. Turgeon AF, Fergusson DA, Clayton L, et al. Liberal or Restrictive Transfusion Strategy in Patients with Traumatic Brain Injury. N Engl J Med 2024;391(8):722-35. doi: 10.1056/NEJMoa2404360 [published Online First: 2024/06/13]
12. Taccone FS, Rynkowski CB, Møller K, et al. Restrictive vs Liberal Transfusion Strategy in Patients With Acute Brain Injury: The TRAIN Randomized Clinical Trial. Jama 2024;332(19):1623-33. doi: 10.1001/jama.2024.20424 [published Online First: 2024/10/09]
13. Tymen R, Dos Santos EC, Taccone FS, et al. Physiological determinants and the red blood cells transfusion decision-making process in non-bleeding critically ill patients: a comprehensive narrative review. Intensive Care Med 2026;52(2):309-23. doi: 10.1007/s00134-026-08304-w [published Online First: 2026/01/26]
